Automatic clutch and brake controlling means in combination with a pattern sewing machine



3,227,115 BINA'IION L. BONO Jan. 4, 1966 AUTOMATIC CLUTCH AND BRAKE CONTROLLING MEANS IN COM WITH A PATTERN SEWING MACHINE 2 Sheets-Sheet "1 Filed July 1, 1963 In vzrn'w r Luig 50 n 0 3,227,115 s IN COMBINATION E L. BONO Jan. 4, 1966 AUTOMATIC CLUTCH AND BRAKE CONTROLLING MEAN WITH A PATTERN SEWING MACHIN Filed July 1, 1965 2 Sheets-Sheet 2 Irv/enfor- United States Patent ()fiice 3,2211 Patented Jan. 4 1965 3,227,115 AUTGMA'IIC CLUTQH AND BRAKE CGNTRG LING MEAN EN CGMBINATION WITH A PATTERN SEWING MACHINE, Luigi Bone, Pavia, Italy, assignor to Necchi Societa per Azioni, Pavia, Italy Filed July 1, 1963, Ser. No. 291,843 Elairns priority, application Italy, July 25, I962, Eatent 692,728 4 Claims. (Cl. 112-2) This invention relates in general to new and useful improvements in sewing machines, and more particularly to a device for automatically controlling a sewing unit including a sewing machine and a fabric holding frame which moves beneath the needle of the sewing machine for making predesigncd seams.

A primary object of this invention is to provide a novel control device for automatically controlling the operation of a sewing unit, the control device being actuated only after the fabric holding frame is in a starting position so that each and every seam sewed by the unit will be the same.

Another object of this invention is to provide a novel automatic control device for a sewing unit which operates to automatically stop the operation of a sewing machine at the end of the sewing at a predetermined seam and when the needle of the sewing machine is in its operative center position so that the sewn fabric may be readily removed from the sewing machine and replaced with other fabric.

Another object of this invention is to provide a novel automatic control device for controlling the operation of a sewing unit which includes a separately operating sewing machine and a separately operating fabric moving device with the control device coordinating the operation of the sewing machine and the fabric moving device.

Still another object of this invention is to provide a novel automatic control device for a sewing unit particularly adapted for sewing a predetermined seam shape, the control device including means for energizing and deenergizing an electromagnet which function as part of the fabric moving mechanism so that the relative shifting of fabric with respect to a sewing machine needle can be controlled in accordance with the operation of the sewing machine.

A further object of this invention is to provide a novel automatic control device for controlling the operation of a sewing machine wherein the sewing machine is driven by a constantly rotating motor through an electric bralre and an electric clutch, and the sewing machine having associated therewith a dynamo with the voltage output of the dynamo controlling the energization of the brake or the clutch, as required, to slow the sewing machine down to a relatively slow speed at the end of a sewing operation whereby continued operation of the sewing machine may be almost instantaneously stopped to assure the stopping of the sewing machine at the end of the desired sewing operation and with the needle in its upper dead-center position.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by a reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a perspective view of the sewing unit which is the subject of this invention and with portions of a stand and support thereof broken away in order to show more clearly the details of the fabric shifting means.

FIGURE 2 is a wiring diagram of the control mechanism for the sewing unit of FIGURE 1.

FIGURE 3 is a partial wiring diagram showing a slight modification of the wiring diagram of FIGURE 2.

Referring now to the drawings in detail, reference is now made to FIGURE 1 wherein there is illustrated by way of example a sewing machine incorporating the invention. The sewing machine is generally referred to by the numeral 1 and has associated therewith a fabric hold ing frame 2 which is movable on a stand or platform 3 of the sewing machine beneath a needle 4 of the sewing machine. The sewing machine 1 is driven by an electric motor A which is connected to the sewing machine through an electromagnetic clutch l3 (FIG. 2). An electromagnetic brake C (FIG. 2) cooperates with the clutch B for the purpose of automatically stopping the operation of the sewing machine 1 when the clutch B is disengaged.

The movements of the fabric holding frame 2 are automatically controlled by the movement of one or more followers or feelers 5 about a shaped contour of a shaped piece 6. The movements of the followers relative to the contour of the shaped piece 6 are controlled by suitable driving means. In a non-illustrated form of the invention, the driving means for the followers may be through an electromagnetic clutch coupled to the electric motor A. The electromagnetic clutch may rotate the shaped piece 6 in a manner not disclosed here.

The specific illustrated form of the invention shown in FIGURES 1 and 2, the shaped piece d is mounted in a fixed position on the underside of the stand 3 and the follower 5, which is illustrated as being in the form of a small shaft, is driven from an electric motor D by means of a reduction unit '7. The follower 5 presses against the shaped piece 6 and is retained in engagement with the contoured portion of the shaped piece 6 by magnetic attraction produced by one or more electromagnets E.

The feeler 5' is rotatably journaled on a mounting memher 8 to which the fabric holding frame 2 is rigidly connected. The mounting member 8 is movable on guides 9 which are carried by another mounting member 10 which is movable in a direction normal to the direction of movement of the mounting member 8 on slides 11 fastened to the stand 3. The follower 5, by rolling in contact with the contoured portion of the shaped piece a, moves from an end 12 of the contoured portion towards an end 12' and proportionately shifts the mounting member 8 with the resultant like movement of the fabric holding frame 2.

In order to achieve a perfect sewing operation, it is necessary that the operation of the sewing machine I be accomplished only when the fabric holding frame 2 is in a definite starting position relative to the shaped piece 6. Also, the stopping of the operation of the sewing machine 1 must occur precisely when the fabric holding frame 2 is in a predetermined final position. The starting and final positions of the sewing machine unit illustrated in FIGURE 1 correspond to the contacting of the follower 5 with the two ends 12 and 3 .2 of the contoured portion of the shaped piece. At these two ends there are mounted two micro switches F1 and F2. At this time it is pointed out that should the contoured portion of the shaped piece 6 be a continuous one, then the positions of the micro-switches Fit and E2 would coincide. In such event, only one micro-switch F would be needed and this would be of a double-throw type so that upon a first operation it would energize the control mechanism and in a second position it would deenergize the control mechanism, as is shown in FIGURE 3.

The stopping of the operation of the sewing machine unit must occur when the needle 4 is raised and completely out of engagement with the fabric being sewn so that it may be possible to remove the fabric from the fabric holding frame 2 and replace the fabric with like fabric. Referring now to FIGURE 2 in particular, it

3 will be seen that a control system of this invention includes a three wire electrical source 13 to which the electric motors A and D are connected, the electric motor A 'being connected to the wires leading from the electrical source 13 at terminals l4, and the electric motor D to the terminal ends of such wires. The wires leading from the electrical source at first incorporated therein a main control switch 15 and then fuses 16. A pair of double pole switches GD and Hi) are mounted in the wires leading from the terminals 14 and the motor D for controlling the How of current through two of the Wires. The switch GD is controlled by means of a remote control switch G, and the switch HD is controlled by means of a remote control switch H.

Intermediate the fuses l6 and the terminals 14 in the two wires in which the switches GD and HD are connected, there are terminals 17 and 1%. The terminal 18 is connected to terminals d, c, b, a, e and f in that order. The terminal 17 is connected to terminals d, c, I) and a in that order. The connection of the last-mentioned terminals to the terminal 18 is through a terminal 19 and a fuse 2%. Other terminals and j are connected to the terminal 17 through the terminal 19 and a fuse 21.

Intermediate the terminals (1 and a are terminals 22 and 2?. A wire leading from the terminal a to the terminal 23 has incorporated therein a switch LG which is controlled by means of a remote control switch L. A wire leading from the terminal 23 to the terminal 22 as incorporated therein a switch GG which is controlled by the remote control switch G. A second wire which extends parallel to the last-mentioned wire and between the terminals 23 and 22 has incorporated therein a switch PG which is controlled by the micro-switch Fit. A coil of the remote control switch G is incorporated in a wire leading between the terminals a and 22.

A pair of terminals 24- and 25 are disposed intermediate the terminals b and b. The terminal 25' is connect-ed to the terminal b directly by means of a wire. A wire leading between the terminals 25 and 24'. has incorporated therein a switch ML operated by a remote control switch M. A second wire leading between the terminals 25 and 24 and parallel to the last-mentioned wire has incorporated therein a switch FL which is controlled by the micro-switch F2. A wire leading from the terminal 24 to the terminal 12 has incorporated therein a coil of the remote control switch L.

Terminals 26 and 27 are disposed between the terminals c and c. A wire leading from the terminal 0 to the terminal 27 has incorporated therein a switch LH which is controlled by the remote control switch L. A first wire leading from the terminal 27 to the terminal 26 has incorporated the-rein a switch HH which is controlled by means of a remote control switch H. A second wire leading between the terminals 27 and 26 are parallel to the last-mentioned wire has incorporated therein a switch PH which is controllable by means of a push button P. A wire loading from the terminal 26 to the terminal c has incorporated therein the coil of the remote control switch H.

Terminals 23 and 2) are disposed intermediate the terminals d and d. A wire directly connects the terminal 29 to the terminal a. A first wire leading from the terminal 29 to the terminal 28 has incorporated therein a switch QM which is operated by means of a push button Q. A second wire leading from the terminal 29 to the terminal 28 has incorporated therein in series switches PM and MM with the switch PM being controlled by the push button P, and the switch MM is controlled by the remote control switch M. A wire leading from the termintl 23 to the terminal a" has incorporated therein the coil of the remote control switch M.

It the contact between the follower and the shaped piece 6 is due to magnetic attraction, a transformer St) is mounted between the terminals e and a with the trans former 38 being controlled by a series mounted switch GE which is controlled by the remote control switch G. The output of the transformer 30 is connected to a rectifier 31 which is protected by means of a fuse 32. The connection between the electromagnet E and the rectifier 31 is protected by means of a fuse 33. The electromagnet E is utilized in a conventional manner to magnetize the shaped piece 6 so that the small shaft which forms a follower 5 can roll along the contoured portion of the shaped piece 6 without slippage.

A pair of transformers 34 and 37 are connected in parallel relation between the terminals 1 and f. The transformer 34 feeds a rectifier 36 through a protecting fuse 35. The transformer 37 feeds a rectifier 38.

A negative pole 39 and the rectifier 36 is connected through a fuse ll to terminals i, m, n, p and h in that order. A positive pole 41 of the rectifier 36 is connected to terminals x, i, m, n, p and it in that order. A positive pole 42 of the rectifier 38 is connected to the terminal x through a fuse 43, terminals 44 and y and a rectifier 45 in that order. A negative pole 46 of the rectifier 38 is connected to a terminal 47. Between the terminals 44 and 47 is placed a condenser 48, and between the terminals 4? and y is connected a resistance 49 of a potentiometer I having a slider 50 which is connected to a negative pole 51 of a tachymetric dynamo or generator R keyed on a shaft (not shown) of the sewing machine 1. A positive pole 52 of the dynamo R is connected to a terminal z which is, in turn, connected to the terminal x through a rectifier 53.

The dynamo R has an energization winding S which is connected in a wire between the terminals [1 and h and is controlled by means of a series switch HS which, in turn, is controlled by the remote control switch H.

A pair of terminals 55 and 56 are disposed between the terminals 1' and i and the terminal 56 being directly connected to the terminal i'. A first wire leading to the terminals 55 and 56 has incorporated therein a switch HB which is controlled by the remote control switch H. A second wire leading to the terminals 55 and 56 parallel to the last-mentioned wire has incorporated therein a controlled switching device or transistor U which includes a collector 57 connected to the terminal 55 and an emitter 58 connected to the terminal 56. A base 59 of the transistor U is connected to the terminal z through a rec tifier 60.

The electromagnetic brake C, a transistor V and switches I-IC and WC are mounted in series between the terminals m and m. The electromagnetic brake C is protected by a rectifier 61, and the switches HC and WC are actuated by remote control switches H and W, respectively. It is to be noted that the wire extending between the terminals mm' is connected to the collector 62 and a emitter 63 of the controlled switching device or transistor V. The transistor V is protected by means of a diode 64. A base 65 of the transistor V is connected to a terminal 66 which is connected to the terminal y by means of a wire having incorporated therein a resistance s7 and a rectifier 68.

A distributor K is connected between the terminals n and n. The distributor K is driven by a shaft of the sewing machine in synchronism with the movement of the needle 4 thereof. The illustrated form of distributor includes three commutator rings 69, '70 and 71 which are electrically connected together. The ring 69 is conductive throughout its periphery and is contacted by a brush '72 which is connected to the terminal n through a terminal 7'3. The ring 70 is a conductor only through a sector 74 thereof of substantially degrees angular extent. A brush '75 rides on the ring 79 and is connected through a resistance '76 to a terminal 77 which, in turn, is connected through a resistance "73 and a terminal 79 to the terminal 11'. The resistance 78 is lower than the resistance '76. A terminal 77 is connected to the terminal 66 by a wire having incorporated therein a switch TC which is controlled by the remote control switch T.

The ring 71 is a conductor only in the vicinity of its sector Stiwhich has an angular extent equal to or less than that of the sector 74. A brush 81 rides on the ring 71 and it is connected to a terminal 82. A wire extending from the terminal 82 to the terminal '79 has incorporated therein in series the coil of the remote control switch T and. a switch ZT which is controlled by a remote control switch Z. The terminal 82 is also connected to the terminal 73 through a wire having incorporated therein a switch TT controlled by the remote control switch T.

The rings 79 and 71 of the distributor K are timed in a manner whereinthe sector 74 comes into contact with the brush 75 at the same instance when the sector 80 comes into contact with the brush 81. The contact between the brush 75 and the sector 74 takes place when the needle 4 nears the upper dead center position of the needle.

A wire directly coupled between the terminal p and p includes a terminal 83, a resistance 84, a terminal 85, a coil of the remote control switch Z, a terminal 86, a terminal 87, and a switch HZ controlled by the remote control switch H, in that order. A parallel wire leading be tween the terminals 83 and 87 has incorporated therein a resistance 88, a terminal 39, a coil of the remote control switch W, a terminal 90 and a switch ZW controlled bythe remote control switch Z.

The remote control switch Z is in the form of a delayed action relay with the delay of this switch being due to a condenser 91 which is connected to the terminal 86 through a bipolar switch ZZ. The switch ZZ, upon the energization of the coil of the switch Z, short-circuits the condenser ?1 through a resistance 93 which is coupled between the switch ZZ and the terminal 92.

The switch W is a delayed action relay like the switch Z with the delay of the switch W being due to a condenser 94 which is connected to the terminal 89 through a terminal 95 and to the terminal 9h through a bipolar switch WW controlled by the remote control switch W. The switch WW, at the energization of the relay or switch W, short-circuits the condenser 94 through a resistance 96 which is connected between the switch WW and the terminal 95.

Reference is now made to FIGURE 3 wherein there is illustrated a modification of the wiring diagram of FIGURE 2 involving only the connections between the terminals 0, b and a on the one hand and the terminals 0, b and a on the other hand. It is to be noted that in this wiring diagram the switches F G and FL have been omitted and they have been replaced by a double-throw double-pole switch which is actuated by the remote control switch H, the double-pole double-throw switch being generally referred to by HF. The four active contacts of the switch HF are connected to the terminals 24, 23, 25 and 22 in that order. The movable contacts of the switch HF are electrically connected together by means of the micro-switch F. It is to be understood that the modified wiring diagram of FIGURE 3 is utilized when the contoured surface and the shaped piece ti is continuous and only one micro-switch F is utilized whereas the wiring diagram shown in FIGURE 2 is utilized when the control is by means of two spaced micro-switches F1 and F2.

OPERATION In order to initiate the operation of the sewing machine 1, the general switch is closed so as to complete the circuit of the wiring diagram of FIGURE 2 with the source of electrical current 13. The closing of the switch 15 results in the energization of the coil of the remote control switch or relay Z with the result that the switches ZT and ZW are closed. The closing of the switch ZW results in the energization of the coil of the remote control switch of relay W. The energization of the relay W results in the opening of the switch WC with the resultant deenergization of the brake C. Should the brush 81 be in contact with the conducting sector as of the ring 71 of the distributor K at the time the switch ZT is closed, the coil of the remote control switch or relay T will also be energized with the result that the switches TC and TT will be closed and the switch TB will be opened. The opening of the switch TB has no effect whatsoever on the operation of the clutch B in that the switch HE is open at this time. As a result, the sewing mach ne 1 remains idle although the motor A is running. The motor D is not operating due to the fact that the switch GD is open, and the electromagnet E is deenergized due to the fact that the switch GE is open. Accordingly, it is possible to lay the work about the sewing machine 1 in order to shift the fabric holding frame 2 and the shaped piece 6 for the closing ofthe switch FG by the operation of the micro-switch FL In the event the circuit is that shown in FIGURE 3, the same will result by the closing of the micro-switch F;

The closing of the switch FG results in the energization of the coil of the remote control switch G with the resultant closing of the contacts of the switches GD and GE. The closing of the contacts of the switches GD and GE prepares the motor D for energization upon the closing of the contacts of the switch HD and energizes the electromagnet E which serves to hold the follower 5 in engagement with the contoured surface of the shaped piece 6.

The sewing machine having thus been prepared for the automatic sewing of fabric carried by the fabric holding frame 2, the beginning of the sewing operation may take place by the pressing of the push button P to close the contact of the switch PH while opening the contact of the switch PM. The closing of the switch PH results in the energization of the coil of the remote control switch H and the resultant closing of the contacts of the switches HD, HH and HB and the opening of the contacts of the switches HC, HZ and HS. The closing of the switch HD results in the energization of the electric motor D to effect the movement of the fabric holding frame 2. At the same time, the closing of the switch HB results in the energization of the clutch B to effect the operation of the sewing machine 1. The opening of the switch HS deenergizes the coil S, and the opening of the switch HZ results in the deenergization of the coils of the relays T and Z, the deenergization of the coil of the relay T resulting from the opening of the switch ZT upon the deenergization of the relay Z. In a like manner, the opening of the switch HZ results in the deenergization of the relay W. The opening of the switch HC results in the deenergization of the brake C although the switch WC is now closed due to the deenergization of the relay W.

At this time it is pointed out that the closing of the switch PH results in a similar functioning of the circuitry of FIGURE 3 with the exception that the deenergization of the coil of the remote control switch H also results in the shifting of the double-pole doublethrow switch HF.

At the end of a sewing operation, the fabric holding frame 2 reaches a final position wherein the follower 5 engages the micro-switch P2 of FIGURE 2 or the microswitch F of FIGURE 3. When this occurs, the switch FL (FIGURE 2) is closed and the coilof the remote control switch L is closed with the resultant opening of the contacts of the switches LH and LG. The opening of these two switches deenergizes the coils of the'remote control switches G and H with the resultant deenergization or" the motor D, the electromagnet E and the clutch B. At the same time the switch HC is closed with the result that current is directed to' the transistor V. Also, current is now delivered tothe energization coil S of the dynamo R. Since the clutch B is disengaged, the speed of the sewing machine 1 rapidly falls to a value of turns per minute, as an example, controlled by the dyna mo R through the potentiometer J. The potentiometer] is previously adjusted so as to have a voltage differential Vi between the slider 50 and the terminal y when the voltage of the dynamo R which voltage is referred to as V1, is higher than the voltage Vj, the resultant current flows to the brake C to effect the operation thereof, while the current flow to the clutch B is insufficient to effect the operation thereof. When the dynamo voltage Vr exceeds the potentimeter voltage Vj, current flows from pole 52 of dynamo R, across rectifier 53, and across terminals X, i, and m therefore arriving at emitter 63 of transistor V, coming out of base 65 and across resistance 67, across the rectifier 68, the pole y, potentiometer resistance 49, and the brush 50 thereby returning to pole 51 of dynamo R. On the other hand, when the voltage Vr of the dynamo R falls below the voltage Vi current is directed to the clutch B and no current is directed to the brake C. It is to be understood that the above mentioned current flow is effected by the rectifiers 60 and 45 on one hand, and the rectifiers 53 and 68 on the other hand.

It is to be understood that since the rectifiers 45, 6t), 53 and 68 are not perfect, the control of the speed of the operation of the sewing machine 1 determined by the dynamo R is a result of the diminution (or respectively of the increase) of the torque transmitted by the clutch B and of the increase (or respectively of the diminution) of the braking couple of the brake C. The speed of the sewing machine stabilizes itself rapidly on the value which results in the voltage Vr being inferior to the voltage Vj by a value just necessary for maintaining the torque required by the sewing machine.

The deenergization of the remote control switch H is followed by a closing of the switch HZ and the energization of the relay Z whose delay is calculated in such a way that it may intervene only when the speed of the sewing machine has stabilized itself to the predetermined reduced speed.

The energization of the relay Z is followed by the closing of the switches ZT and ZW. The closing of the switch ZT effects the energization of the relay T as soon as the conducting sector 80 of the ring 71 comes into contact with the brush 81. The following energization of the relay T results in the opening of the contact of the switch TB and the complete deenergization of the clutch B for the closing of the contact of the switch TC. The closing of the switch TC is followed by the complete energization of the brake C through the conducting sector 74 of the ring 70 so as to effect the stopping of the sewing machine 1 with the needle 4 in its upper dead center position. The closing of the contact of the switch ZW is followed with a delay calculated in such a Way that the sewing machine 1 be completely stopped after which the contact of the switch WC is opened to deenergize the brake C.

It is to be understood that in the arrangement of FIGURE 3, the fabric holding frame 2 is in a position for the renewing of a sewing operation after the fabric has been changed. However, in the arrangement of FIG- URE 2, after the stopping of the sewing operation, it is necessary to bring by hand the fabric holding frame 2 back to its starting position to initiate a new sewing cycle.

The sewing cycle can be discontinued at any moment by pressing the push button Q in order to close the contact of the switch QM. This results in the energization of the remote control switch M and the closing of the switches MM and ML. This results in the energization of the remote control switch L to open the switches LH and LG and to effect the stopping of the sewing operation in the same manner as if the switch FL were closed. The remote control switch M is self-energizing through the switches MM and PM, and when restarting of the operation of the sewing machine is desired, it is necessary to press the push button P.

From the foregoing, it will be readily apparent that the operation of the sewing machine 1 is automatically controlled so as to effect the stopping thereof at all times 8. with the needle 4 in the upper dead center position. At the same time, although the operation of the sewing machine is automatic, it may be readily manually stopped at any time in the sewing operation with the sewing machine in the upper dead center position.

Although only a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that other modifications may be made in the automatic operation of the sewing machine within the spirit and scope of this invention, as defined in the appended claims.

I claim:

1. A sewing unit comprising sewing machine and fabric holding and shifting means, means for separately operating said sewing machine and said shifting means, and control means for automatically operating said sewing machine and said shifting means in accordance with the position of said fabric holding means, and wherein said fabric shifting means includes a shaped piece having a contoured surface, a follower, electromagnetic means coupled with said shaped piece for retaining said follower in engagement with said contoured surface, means for rotating said follower to move said follower along said contoured surface, and means coupling said follower to said fabric holding means to move the same, said sewing machine operating means including an electric clutch and an electric brake, a first control circuit for controlling the energization of said electromagnetic means and operating said follower rotating means, and a second control circuit for operating said brake and clutch, and wherein said first control circuit is an alternating current circuit and said second control circuit is a direct current circuit, said second circuit including a generator driven by said sewing machine and coupled to produce a clutch and brake controlling current at the termination of a sewing operation to slow the operation of said sewing machine at the termination of a desired sewing operation immediately prior to the final stoppage of the sewing machine.

2. A sewing unit comprising a sewing machine and fabric holding and shifting means, means for separately operating said sewing machine and said shifting means, and control means for automatically operating said sewing machine and said shifting means in accordance with the position of said fabric holding means, and wherein said fabric shifting means includes a shaped piece having contoured surface, a follower, electromagnetic means coupled with said shaped piece for retaining said follower in engagement with said contoured surface, means for rotating said follower to move said follower along said contoured surface, and means coupling said follower to said fabric holding means to move the same, said sewing machine operating means including an electric clutch and an electric brake, a first control circuit for controlling the energization of said electromagnetic means and operating said follower rotating means, and a second control circuit for operating said brake and clutch, and wherein said first control circuit is an alternating current circuit and said second control circuit is a direct current circuit, said second circuit including a generator driven by said sewing machine and coupled to produce a clutch and brake controlling current at the termination of a sewing operation to slow the operation of said sewing machine at the termination of a desired sewing operation immediately prior to the final stoppage of the sewing machine, said second circuit being coupled to said first circuit through rectifiers.

3. A sewing unit comprising a sewing machine and fabric holding and shifting means means for separately operating said sewing machine and said shifting means, and control means for automatically operating said sewing machine and said shifting means in accordance with the position of said fabric holding means, and wherein said sewing machine operating means includes an electric clutch and an electric brake, and said control means including an electrical circuit comprising a generator driven by said sewing machine to produce a speed variable voltage for providing a clutch and brake controlling current at the termination of a sewing operation to slow the operation of said sewing machine at the termination of a desired sewing operation immediately prior to the final stoppage of the sewing machine, said electrical circuit including means providing a fixed voltage in opposition to the speed variable voltage of the output of said generator, and wherein the flow of current resulting from the opposition of said generator produced variable voltage to the fixed voltage is conveyed either to the brake or to the clutch, depending upon which of said voltages is higher, by means of a group of rectifiers located in said electrical circuit.

4. A sewing unit comprising a sewing machine and fabric holding and shifting means, means for separately operating said sewing machine and said shifting means, and control means for automatically operating said sewing machine and said shifting means in accordance with the position of said fabric holding means, and wherein said sewing machine operating means includes an electric clutch and an electric brake, and said control means including an electrical circuit comprising a generator driven by said sewing machine and coupled to produce a speed variable voltage for providing a clutch and brake controlling current at the termination of a sewing operation to slow the operation of said sewing machine at the termination of a desired sewing operation immediately prior to the final stoppage of the sewing machine, said electrical circuit including means providing a fixed voltage in opposition to the speed variable voltage of the output of said generator, and said circuit comprising controlled switching devices which are responsive to the current which results from the combined said voltages to energize said clutch or brake.

References Cited by the Examiner UNITED sTATEs PATENTS 2,920,221 1/1960 Schwab 112-219 2,958,302 11/1960 Frankel at al. 112-219 3,084,640 4/1963 Hayes et a1. 112-2 3,149,593 9/1964 Johnson 112 219 3,160,128 12/1964 Heidt "112-219 FOREIGN PATENTS 581,451 8/1958 Italy.

JORDAN FRANKLIN, Primary Examiner. 

4. A SEWING UNIT COMPRISING A SEWING MACHINE AND FABRIC HOLDING AND SHIFTING MEANS, MEANS FOR SEPARATELY OPERATING SAID SEWING MACHINE AND SAID SHIFTING MEANS, AND CONTROL MEANS FOR AUTOMATICALLY OPERATING SAID SEWING MACHINE AND SAID SHIFTING MEANS IN ACCORDANCE WITH THE POSITION OF SAID FABRIC HOLDING MEANS, AND WHEREIN SAID SEWING MACHINE OPERATING MEANS INCLUDES AN ELECTRIC CLUTCH AND AN ELECTRIC BRAKE, AND SAID CONTROL MEANS INCLUDING AN ELECTRICAL CIRCUIT COMPRISING A GENERATOR DRIVEN BY SAID SEWING MACHINE AND COUPLED TO PRODUCE A SPEED VARIABLE VOLTAGE FOR PROVIDING A CLUTCH AND BRAKE CONTROLLING CURRENT AT THE TERMINATION OF A SEWING OPERATION TO SLOW THE OPERATION OF SAID SEWING MACHINE AT THE TERMINATION OF A DESIRED SEWING OPERATION IMMEDIATELY PRIOR TO THE FINAL STOPPAGE OF THE SEWING MACHINE, SAID ELECTRICAL CIRCUIT INCLUDING MEANS PROVIDING A FIXED VOLTAGE IN OPPOSITION TO THE SPEED VARIABLE VOLTAGE OF THE OUTPUT OF SAID GENERATOR, AND SAID CIRCUIT COMPRISING CONTROLLED SWITCHING DEVICES WHICH ARE RESPONSIVE TO THE CURRENT WHICH RESULTS FROM THE COMBINED SAID VOLTAGES TO ENERGIZE SAID CLUTCH OR BRAKE. 